The publisher Henry Holt/Batsford issued a book called Positional Play in 1996. It was edited by Dvoretsky and Artur Yusupov, and included articles by Vladimir Kramnik, Yusupov, Evgeni Bareev and some of Mark's other students. There were longish chapters on prophylaxis, maneuvering, planning, opposite colour bishops, etc.
In 2002, the publisher Edition Olms issued a new book called School of Chess Excellence 3: Strategic Play. It is a collection of short articles by Dvoretsky himself on topics like the initiative, pawn breaks, blockade, the two bishops, mysterious rook moves, etc. I don't think there is much overlap between the two books.
In 2008, Edition Olms acquired the rights to Batsford's 1996 Positional Play book, and reissued it as Secrets of Positional Play: School of Future Champions 4. There are a couple of new chapters by Maxim Dlugy and Yusupov, and the 1996 chapters have been retranslated, and errors corrected.
There is a review of this most recent book here:
http://www.chesscafe.com/text/review693.pdf
Does anyone know the difference between the two Dvoretsky books School of Chess Excellence 3: Strategic Play and Secrets of Positional Play: School of Future Champions 4? Are they similar enough that if you've read one there's little point in the other etc? I'm sure there's some overlap, I just don't know how much. Thanks so much in advance.